Introduction Of 66kV Infrastructure in UAE Offshore Oil Gas Industry

摘要

This paper presents a case study by NPCC for the selection of offshore power distribution voltage in AlYasat's,Belbazem Feed Project.The project involves large offshore power delivery to three ESP based WHTplatform through subsea umbilical.This necessitates detailed study for the right selection of distributionvoltage with an objective to minimize offshore cost.The study involved survey of existing medium voltage transmission practice in most of the ADNOCoffshore facilities and took into consideration of new technologies and development in offshore renewableenergy sector with regard to 66kV infrastructure.The study considers 33kV and 66kV as the preferredcandidates for comparison in offshore distribution voltage.Comparison is done based on subsea cabledesign,subsea power cable cross section,voltage drop,power loss,cable charging breaking current,GIStechnology,CAPEX and OPEX.For the delivery of large offshore power over long distance,the study resulted in the selection of 66kVdistribution voltage.66kV design reduces subsea cable cross section to significant extent while maintaininglower voltage drop and power loss as compared to 33kV design.Lower cable cross section results inreduction in cable weight,lower packing and transportation cost,less cable joints for long cables andincrease in offshore installation efficiency.High voltage power transmission through long distance subseacable involves substantial handling of cable charging current by breakers.The breaker tested as per IECfavors 66kV design since the breakers are tested at higher cable charging breaking limit(2.5 times)ascompared to 33kV.This eliminates the requirement of shunt reactor in 66kV.New development in 66kVoffshore renewable energy market such as introduction of wet type design in subsea cable,introductionof euromold cable connectors and compact GIS solutions makes 66kV design very cost competitive.Thebenefits which 66kV design offers lowers offshore CAPEX and OPEX.The introduction of 66kV is novel to ADNOC and a major shift from existing practice in UAE oil &gas industry.